docs: def add(gandi, resource, vhost, zone_alter, backend, port, ssl, private_key,
          poll_cert):
      """ Add a backend or a vhost on a webaccelerator """
      result = []
      if backend:
          backends = backend
          for backend in backends:
              # Check if a port is set for each backend, else set a default port
              if 'port' not in backend:
                  if not port:
                      backend['port'] = click.prompt('Please set a port for '
                                                     'backends. If you want to '
                                                     ' different port for '
                                                     'each backend, use `-b '
                                                     'ip:port`', type=int)
                  else:
                      backend['port'] = port
              result = gandi.webacc.backend_add(resource, backend)
  
      if vhost:
          if not gandi.hostedcert.activate_ssl(vhost, ssl, private_key,
                                               poll_cert):
              return
          vhosts = vhost
          for vhost in vhosts:
              params = {'vhost': vhost}
              if zone_alter:
                  params['zone_alter'] = zone_alter
              result = gandi.webacc.vhost_add(resource, params)
      return result